2699: use xthreaded, not threaded in apart
806: Improve code style
modify xthreaded and xreplace to fail gracefully

- xreplace leave args that don't implement xreplace alone
- xtrheaded allows objects that don't rebuild to return unchanged
Hints now return eq also
ipython: reenable mathjax and fix issue 3537.
Revert "Remove IPython sniffing" to fix part of issue 3728.

This reverts commit a4541e3af31eb33f4559d56e069d1150f332194b.
Don't load latex in ipython-console (terminal console).
ipython pretty printing tests should not rely on use_unicode=True.
Add an example and Sphinx doc for heurisch_wrapper.
Don't rely on bool(Relational) in the Piecewise solver.

Fixes issue 2961:
__nonzero__ method of Rel breaks solve of Piecewise functions
http://code.google.com/p/sympy/issues/detail?id=2961
Solution is valid iff Piecewise conditions are satisfied.
remove whitespace
MatrixElement Q.real/integer/complex
Merge pull request #2009 from raoulb/jacobi_poly_norm

Normalized Jacobi polynomials
Merge pull request #2043 from Manoj-Kumar-S/bug

Fixes Issue 3780
Merge pull request #2036 from hacman/totient

Symbolic Totient
If substitution in gosper_sum fails - take limit instead (issue 2934)
Addition of hypertangent and exponential cases to parametric differntial equations

 added code exponential for to special denom

added code for tangent cases to special denom

added code for tangent cases to special denom

First attempt to solve the section 5.12

first attempt to solve section 5.12 and related problems

First Attempt to implement section 5.12 and related problems

added hypertangent test cases for param special

deleted binary file
modifications to simplify

== add quick exit for simplify if expr is Atom

== 3712: try return factored expression more often

== 3730: use as_content_primitive and cancel
Merge pull request #1925 from smichr/3712

3712 - simplify changes